Sql Error ? ---> «monoDeveloper C#»

using MySql.Data.MySqlClient; 
        public class mySql
        {
                public static string mysql_user = "mysql -u mailsql -p mailsql";
                public static string mysql_pass = "pass";
                public static string ConnectSql =(mysql_user + mysql_pass);
                MySqlConnection mysql_connect = new MySqlConnection(ConnectSql);
 
                MySqlCommand mysql_query = new MySqlCommand("SELECT `username` FROM `users`;", mysql_connect);
        }

Main.cs(74,74): Error CS0236: A field initializer cannot reference the nonstatic field, method, or property `sqlconsole.mySql.mysql_connect' (CS0236) (sql console)